The most common cause of residential fires is unattended cooking where the user fails to properly attend to cooking because they are distracted, forgetful, drawn away by some emergency or simply careless. Fires can start for example, when cooking oil ignites within a hot vessel, or when oil spills onto the hot cooking element surface, or when contents of a pot dry out and ignite or when adjacent flammable materials come into contact with hot surfaces. Of particular risk are cooking appliances used by the elderly who experience memory lapses or by inexperienced cooks unfamiliar with the risks.
A prior art approach to reducing the fire risk uses a stove dial timing device to prompt the user to return to the stove periodically to monitor the cooking process. An example is described in U.S. Pat. No. 7,816,818 that uses a control dial with a built-in timer and audible alarm. The timer emits an audible alarm at a regular interval to remind the user to return to the stove periodically, to turn off the alarm and therefore reduce the likelihood of fires caused by unattended cooking.
There are shortcomings of the prior art described in U.S. Pat. No. 7,816,818 as follows. The timer is set to a fixed time regardless of the heat output of the burner. The timer relies on the user to set the fixed time through the selection of a mode of operation. This is likely to cause incorrect times to be set or the function may be ignored completely. A default time may be selected that is inappropriate for the food material being cooked. For example, frying in oil at high temperature settings can be especially dangerous if unattended even for a short period. The oil can ignite at high heat or oil can splatter and ignite on hot adjacent surfaces. Therefore unattended cooking, with oil at high heat is inherently much more likely to create a fire hazard quickly, whereas simmering a pot of liquid at low heat is much less likely to cause a fire.
The alarm in U.S. Pat. No. 7,816,818 is located within the timer dial which has limited space available on the stove panel surface and the size limits the maximum volume due to space constraints created by the accompanying speaker, warning lights, battery and circuit boards. Elderly users with impaired hearing for example may not be able to hear the alarm if they have left the kitchen area. Noise from televisions or radios in other rooms may mask the sound of an alarm emitted from a cooking appliance at a distance away from the user. The timer dial in U.S. Pat. No. 7,816,818 relies on mechanical buttons for setting and resetting of the timer. Mechanical buttons are unreliable in an environment where they will be exposed to steam and oil vapour from the cooking process. Mechanical parts may corrode or receive oil mist that attracts dust which clogs the moving parts.
Most noticeably, the timer dials in U.S. Pat. No. 7,816,818 are independent from each other and are not coordinated with each other. Where several burners are used simultaneously for cooking, multiple alarms will be activated independently depending on when the burner and timer was turned on. This will cause significant annoyance to the user who will be bombarded by multiple alarms and will be required to return to the stove every few minutes to reset a timer dial. This independent feature alone may prompt users to abandon use of the timer dials altogether.
Further the device in U.S. Pat. No. 7,816,818 is an alarm only which can be ignored or may not be heard by the user. If the user does not respond to the audible alarm the device in U.S. Pat. No. 7,816,818 has no ability to take further action to prevent a fire. If a user completely neglects the cooking process, for example, has a heart attack, falls or has an emergency situation to deal with, the stove continues to operate and presents a significant fire risk especially for elderly users, diabetics and other users with major health risks.
Features that distinguish the present invention from the background art will be apparent from review of the disclosure, drawings and description of the invention presented below.